Sir william petty (1623-1687) poses in this painting. He holds a skull in his right hand while his left hand rests on plate 3 of adriaan van den spiegel's de humani corporis fabrica [on the fabric of the human body] (1627). Object Type: painting. Genre: portrait. Date: circa 1649-1650. Dimensions: height: 124.5 cm (49 in) ; width: 100.3 cm (39.4 in). Medium: oil on canvas. Depicted People: William Petty. Collection: National Portrait Gallery. SirWilliamPetty